Question

Given below are two statements:
Statement I: Sickle cell trait protects humans from malaria.
Statement II: Sickle cell trait can be transmitted even if both the parents are heterozygous for the $\beta$-globin gene.

• A. Both Statement I and Statement II are correct
• B. Both Statement I and Statement II are incorrect
• C. Statement I is correct but Statement II is incorrect
• D. Statement I is incorrect but Statement II is correct

Hint:

Heterozygote Advantage: Carriers are protected against Malaria.

Answer 1

The Correct Option is A

Step 1: Concept
Sickle cell anemia is an autosomal recessive disorder caused by a mutation in the HBB gene.

Step 2: Meaning
"Trait" refers to the heterozygous state (HbAS), where an individual has one normal allele and one sickle allele.

Step 3: Analysis
Statement I is correct; individuals with the sickle cell trait have a survival advantage in malaria-endemic regions because the parasite cannot thrive as well in their red blood cells. Statement II is also correct; if both parents are heterozygous (carriers), there is a 50% chance for each child to also have the trait (and a 25% chance to have the disease).

Step 4: Conclusion
Both statements accurately reflect the genetics and biological significance of the sickle cell trait. Final Answer: (A)